when i get in between 80 - 100 kms per hour..I feel like my truck is shuttering or misfiring..any other speeds,,the truck seems to work alright...would anyone know what this problem would be....thanks in advance

 

I would guess it's either a low level missfire (any codes?) or you have transmission shudder. I know almost nothing about transmissions but from what I've read a shudder is not uncommon and can come in at various shift points as well. Sometimes a trans oil change can help. What engine do you have and how many miles?

 

Could be a coil. Mine had the same symptons, ended up being 3 coils. Mine did throw a code, but from what I have read, that isn't always the case.

 

i am not getting a engine code....I am running the 5.4L engine and i got about 174,000 Kms on the truck..is there another way to find out if its the coil wether or not its giving the code or not..

 

Have the spark plugs ever been changed? What about the tranny fluid?

 

Not sure what you have around you in the way of auto part stores but Auto Zone, Murrays, and others around here will check you vehicle for codes for free. May want to check it out. If no codes are found then you may have to start changing some parts. Can get expensive especially if your not real lucky (I can relate..). I would start with the plugs (Motorcraft, Motorcraft or Motorcraft). You can get COP's online fairly inexpensive. I think Global is one site. With your mileage you must be getting ready for new sparkplugs anyway? I think one of these two components may be your problem but again I hear of transmission shudder here as well. May want to go over to the transmission section and ask around as well. Good luck

 

The best way to get the computer to detect missfires is put the engine under a load. Big long up hill works good something like that. Or just be pationt it will detect it eventually. Sounds like a missfire to me to.